From mboxrd@z Thu Jan 1 00:00:00 1970 MIME-Version: 1.0 Date: Wed, 19 Dec 2018 07:18:13 -0600 References: <83adc98adc1760a0fad87d81d171e1dac783e7e5.1544235317.git.thinhn@synopsys.com> <20181218163858.GA12336@bogus> <30102591E157244384E984126FC3CB4F639AB1BC@us01wembx1.internal.synopsys.com> In-Reply-To: <30102591E157244384E984126FC3CB4F639AB1BC@us01wembx1.internal.synopsys.com> Message-ID: Subject: Re: [PATCH v2 1/4] usb: dwc3: Add property snps,refclk-period-ns From: Rob Herring Content-Type: text/plain; charset="UTF-8" To: Thinh Nguyen Cc: Felipe Balbi , Linux USB List , devicetree@vger.kernel.org, Mark Rutland , John Youn List-ID: On Tue, Dec 18, 2018 at 6:22 PM Thinh Nguyen wrote: > > Hi Rob, > > On 12/18/2018 8:39 AM, Rob Herring wrote: > > On Fri, Dec 07, 2018 at 06:27:30PM -0800, Thinh Nguyen wrote: > >> This patch introduces property "snps,refclk-period-ns" to inform the > >> controller of the reference clock period. If the reference clock period > >> is different from the default Core Consultant setting, then this > >> property can be set to the reference clock period. > >> > >> This property does not control the reference clock rate. The controller > >> uses this value to perform internal timing calculations that are based > >> on the reference clock. > >> > >> Signed-off-by: Thinh Nguyen > >> --- > >> Changes in v2: > >> - Split from "usb: dwc3: Add reference clock properties" > >> - Revise commit message and property description > >> > >> Documentation/devicetree/bindings/usb/dwc3.txt | 2 ++ > >> 1 file changed, 2 insertions(+) > >> > >> diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt b/Documentation/devicetree/bindings/usb/dwc3.txt > >> index 8e5265e9f658..b7e67edff9b2 100644 > >> --- a/Documentation/devicetree/bindings/usb/dwc3.txt > >> +++ b/Documentation/devicetree/bindings/usb/dwc3.txt > >> @@ -99,6 +99,8 @@ Optional properties: > >> this and tx-thr-num-pkt-prd to a valid, non-zero value > >> 1-16 (DWC_usb31 programming guide section 1.2.3) to > >> enable periodic ESS TX threshold. > >> + - snps,refclk-period-ns: if set, this value informs the controller of the > >> + reference clock period in nanoseconds. > > Shouldn't you be able to retrieve the refclk frequency and then > > calculate the period? > > The thing is we cannot determine the ref_clk frequency for some devices > that don't specify their clocks. So I think we should have an option to > inform the controller of the ref_clk period for those devices. Specifying the clock should be mandatory (if you want/need this feature). It just requires a fixed-clock node at a minimum. Rob From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 Subject: [v2,1/4] usb: dwc3: Add property snps,refclk-period-ns From: Rob Herring Message-Id: Date: Wed, 19 Dec 2018 07:18:13 -0600 To: Thinh Nguyen Cc: Felipe Balbi , Linux USB List , devicetree@vger.kernel.org, Mark Rutland , John Youn List-ID: T24gVHVlLCBEZWMgMTgsIDIwMTggYXQgNjoyMiBQTSBUaGluaCBOZ3V5ZW4gPHRoaW5oLm5ndXll bkBzeW5vcHN5cy5jb20+IHdyb3RlOgo+Cj4gSGkgUm9iLAo+Cj4gT24gMTIvMTgvMjAxOCA4OjM5 IEFNLCBSb2IgSGVycmluZyB3cm90ZToKPiA+IE9uIEZyaSwgRGVjIDA3LCAyMDE4IGF0IDA2OjI3 OjMwUE0gLTA4MDAsIFRoaW5oIE5ndXllbiB3cm90ZToKPiA+PiBUaGlzIHBhdGNoIGludHJvZHVj ZXMgcHJvcGVydHkgInNucHMscmVmY2xrLXBlcmlvZC1ucyIgdG8gaW5mb3JtIHRoZQo+ID4+IGNv bnRyb2xsZXIgb2YgdGhlIHJlZmVyZW5jZSBjbG9jayBwZXJpb2QuIElmIHRoZSByZWZlcmVuY2Ug Y2xvY2sgcGVyaW9kCj4gPj4gaXMgZGlmZmVyZW50IGZyb20gdGhlIGRlZmF1bHQgQ29yZSBDb25z dWx0YW50IHNldHRpbmcsIHRoZW4gdGhpcwo+ID4+IHByb3BlcnR5IGNhbiBiZSBzZXQgdG8gdGhl IHJlZmVyZW5jZSBjbG9jayBwZXJpb2QuCj4gPj4KPiA+PiBUaGlzIHByb3BlcnR5IGRvZXMgbm90 IGNvbnRyb2wgdGhlIHJlZmVyZW5jZSBjbG9jayByYXRlLiBUaGUgY29udHJvbGxlcgo+ID4+IHVz ZXMgdGhpcyB2YWx1ZSB0byBwZXJmb3JtIGludGVybmFsIHRpbWluZyBjYWxjdWxhdGlvbnMgdGhh dCBhcmUgYmFzZWQKPiA+PiBvbiB0aGUgcmVmZXJlbmNlIGNsb2NrLgo+ID4+Cj4gPj4gU2lnbmVk LW9mZi1ieTogVGhpbmggTmd1eWVuIDx0aGluaG5Ac3lub3BzeXMuY29tPgo+ID4+IC0tLQo+ID4+ IENoYW5nZXMgaW4gdjI6Cj4gPj4gLSBTcGxpdCBmcm9tICJ1c2I6IGR3YzM6IEFkZCByZWZlcmVu Y2UgY2xvY2sgcHJvcGVydGllcyIKPiA+PiAtIFJldmlzZSBjb21taXQgbWVzc2FnZSBhbmQgcHJv cGVydHkgZGVzY3JpcHRpb24KPiA+Pgo+ID4+ICBEb2N1bWVudGF0aW9uL2RldmljZXRyZWUvYmlu ZGluZ3MvdXNiL2R3YzMudHh0IHwgMiArKwo+ID4+ICAxIGZpbGUgY2hhbmdlZCwgMiBpbnNlcnRp b25zKCspCj4gPj4KPiA+PiBkaWZmIC0tZ2l0IGEvRG9jdW1lbnRhdGlvbi9kZXZpY2V0cmVlL2Jp bmRpbmdzL3VzYi9kd2MzLnR4dCBiL0RvY3VtZW50YXRpb24vZGV2aWNldHJlZS9iaW5kaW5ncy91 c2IvZHdjMy50eHQKPiA+PiBpbmRleCA4ZTUyNjVlOWY2NTguLmI3ZTY3ZWRmZjliMiAxMDA2NDQK PiA+PiAtLS0gYS9Eb2N1bWVudGF0aW9uL2RldmljZXRyZWUvYmluZGluZ3MvdXNiL2R3YzMudHh0 Cj4gPj4gKysrIGIvRG9jdW1lbnRhdGlvbi9kZXZpY2V0cmVlL2JpbmRpbmdzL3VzYi9kd2MzLnR4 dAo+ID4+IEBAIC05OSw2ICs5OSw4IEBAIE9wdGlvbmFsIHByb3BlcnRpZXM6Cj4gPj4gICAgICAg ICAgICAgICAgICAgICAgdGhpcyBhbmQgdHgtdGhyLW51bS1wa3QtcHJkIHRvIGEgdmFsaWQsIG5v bi16ZXJvIHZhbHVlCj4gPj4gICAgICAgICAgICAgICAgICAgICAgMS0xNiAoRFdDX3VzYjMxIHBy b2dyYW1taW5nIGd1aWRlIHNlY3Rpb24gMS4yLjMpIHRvCj4gPj4gICAgICAgICAgICAgICAgICAg ICAgZW5hYmxlIHBlcmlvZGljIEVTUyBUWCB0aHJlc2hvbGQuCj4gPj4gKyAtIHNucHMscmVmY2xr LXBlcmlvZC1uczogaWYgc2V0LCB0aGlzIHZhbHVlIGluZm9ybXMgdGhlIGNvbnRyb2xsZXIgb2Yg dGhlCj4gPj4gKyAgICAgICAgICAgICAgICAgICAgcmVmZXJlbmNlIGNsb2NrIHBlcmlvZCBpbiBu YW5vc2Vjb25kcy4KPiA+IFNob3VsZG4ndCB5b3UgYmUgYWJsZSB0byByZXRyaWV2ZSB0aGUgcmVm Y2xrIGZyZXF1ZW5jeSBhbmQgdGhlbgo+ID4gY2FsY3VsYXRlIHRoZSBwZXJpb2Q/Cj4KPiBUaGUg dGhpbmcgaXMgd2UgY2Fubm90IGRldGVybWluZSB0aGUgcmVmX2NsayBmcmVxdWVuY3kgZm9yIHNv bWUgZGV2aWNlcwo+IHRoYXQgZG9uJ3Qgc3BlY2lmeSB0aGVpciBjbG9ja3MuIFNvIEkgdGhpbmsg d2Ugc2hvdWxkIGhhdmUgYW4gb3B0aW9uIHRvCj4gaW5mb3JtIHRoZSBjb250cm9sbGVyIG9mIHRo ZSByZWZfY2xrIHBlcmlvZCBmb3IgdGhvc2UgZGV2aWNlcy4KClNwZWNpZnlpbmcgdGhlIGNsb2Nr IHNob3VsZCBiZSBtYW5kYXRvcnkgKGlmIHlvdSB3YW50L25lZWQgdGhpcwpmZWF0dXJlKS4gSXQg anVzdCByZXF1aXJlcyBhIGZpeGVkLWNsb2NrIG5vZGUgYXQgYSBtaW5pbXVtLgoKUm9iCg==